![]() Version: 9.3.28.v20191105 |
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It is sometimes useful to preserve existing Sessions across restarts of Jetty.
The HashSessionManager
supports this feature.
If you enable persistence, the HashSessionManager
saves all existing, valid Sessions to disk before shutdown completes.
On restart, Jetty restores the saved Sessions.
A SessionManager
does just what its name suggests – it manages the lifecycle and state of sessions on behalf of a webapp.
Each webapp must have its own unique SessionManager
instance.
Enabling persistence is as simple as configuring the HashSessionManager
as the SessionManager
for a webapp and telling it where on disk to store the sessions:
<Configure class="org.eclipse.jetty.webapp.WebAppContext">
.
.
.
<Set name="sessionHandler">
<New class="org.eclipse.jetty.server.session.SessionHandler">
<Arg>
<New class="org.eclipse.jetty.server.session.HashSessionManager">
<Set name="storeDirectory">your/chosen/directory/goes/here</Set>
</New>
</Arg>
</New>
</Set>
.
.
.
</Configure>
The above uses an example of a context configuration file.
If you want to persist the sessions from multiple webapps:
HashSessionManager
for each.storeDirectory
.You might need to ensure that the sessions are loaded AFTER the servlet environment starts up (by default, Jetty eagerly loads sessions as part of the container startup, but before it initializes the servlet environment). For example, the Wicket web framework requires the servlet environment to be available when sessions are activated.
Using SessionManager.setLazyLoad(true)
, Jetty loads sessions lazily either when it receives the first request for a session, or the session scavenger runs for the first time, whichever happens first.
Here’s how the configuration looks in XML:
<Set name="sessionHandler">
<New class="org.eclipse.jetty.server.session.SessionHandler">
<Arg>
<New class="org.eclipse.jetty.server.session.HashSessionManager">
<Set name="lazyLoad">true</Set>
</New>
</Arg>
</New>
</Set>
To enable session persistence for the Jetty Maven plugin, set up the HashSessionManager
in the configuration section like so:
<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>9.0.0.RC2 (or current version)</version>
<configuration>
<!-- ... -->
<webAppConfig implementation="org.eclipse.jetty.maven.plugin.JettyWebAppContext">
<defaultsDescriptor>${project.build.outputDirectory}/META-INF/webdefault.xml</defaultsDescriptor>
<contextPath>${jetty.contextRoot}</contextPath>
<sessionHandler implementation="org.eclipse.jetty.server.session.SessionHandler">
<sessionManager implementation="org.eclipse.jetty.server.session.HashSessionManager">
<storeDirectory>${project.basedir}/target/jetty-sessions</storeDirectory>
<idleSavePeriod>1</idleSavePeriod>
</sessionManager>
</sessionHandler>
</webAppConfig>
<!-- ... -->
</configuration>
</plugin>